A secondary battery, which has high application easiness according to a product group and an electric characteristic, such as a high energy density, has been universally applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), or an energy storage system (ESS) driven by an electric driving source, as well as a portable device. The secondary battery attracts attention as a new energy source that is environmentally-friendly and has improved energy efficiency in that it is possible to innovatively decrease use of fossil fuel, which is the primary advantage, while not generating a by-product when using energy.
The secondary battery includes positive electrode and negative electrode current collectors, a separator, an active material, an electrolyte, and the like and is repeatedly chargeable/dischargeable by an electro-chemical reaction between constituent elements. For example, a widely used lithium polymer secondary battery has an operation voltage of about 3.7 V to 4.2 V. Accordingly, in order to obtain a high output battery pack applied to the EV and the like, the battery pack is configured by connecting a plurality of unit secondary battery cells in series.
In addition to the basic structure, the battery pack additionally includes a battery management system (BMS), to which an algorithm for a power supply control for a driving load of a motor and the like, a measurement of an electric characteristic value, such as a current or a voltage, a charging/discharging control, a voltage equalization control, an estimation of a state of charge (SOC), and the like is applied to monitor and control a state of the secondary battery.
As the number of functions of the BMS is increased, several scheduling is operated by software. The schedulers (tasks and timers) slightly influence operations due to a priority of the corresponding scheduling, and when an excessive load is applied to one scheduler, the scheduling breaks down. Particularly, the related art does not have a function of checking the corresponding scheduler during an operation after the scheduler is initially set, so that there is a problem in stability.